Method for transmitting srs in wireless communication system and terminal for same

ABSTRACT

A method for transmitting a sounding reference symbol (SRS) by a terminal in a wireless communication system can comprise the steps of: receiving, from a base station, control information comprising a first indicator for indicating localized SRS transmission; and transmitting a localized SRS in a particular symbol on the basis of the first indicator.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, to a method of transmitting a sounding referencesymbol (SRS) in a wireless communication system and terminal for thesame.

BACKGROUND ART

With the introduction of a new radio access technology (RAT) system, asmore and more communication devices require greater communicationcapacity, there is a need for mobile broadband communication enhancedover conventional Radio Access Technology (RAT). In addition, massiveMachine Type Communications (MTC) capable of providing a variety ofservices anywhere and anytime by connecting multiple devices and objectsis one of important issues to be considered in the next-generationcommunications. Communication system design considering services/UEssensitive to reliability and latency is also under discussion. Thus, thenew RAT is to provide services considering enhanced Mobile Broadband(eMBB) communication, massive MTC (mMTC), and Ultra-Reliable and LowLatency Communication (URLLC).

DISCLOSURE Technical Problem

An object of the present disclosure is to provide a method for aterminal (or user equipment (UE)) to transmit an SRS.

Another object of the present disclosure is to provide a UE fortransmitting an SRS in a wireless communication system.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

Technical Solution

In an aspect of the present disclosure, provided herein is a method oftransmitting a sounding reference symbol (SRS) by a user equipment (UE)in a wireless communication system. The method may include: receiving,from a base station (BS), control information including a firstinstruction for instructing to transmit a localized SRS; andtransmitting the localized SRS in a specific symbol based on the firstinstruction.

The control information may further include a second instruction forinstructing to multiplex and transmit the localized SRS and an uplinkcontrol channel in the specific symbol. The localized SRS and the uplinkcontrol channel may be multiplexed and transmitted in the specificsymbol based on the second instruction. The method may further includetransmitting an uplink control channel or a whole-band SRS in a symboladjacent to the specific symbol.

The control information may further include information on a startingposition of the localized SRS in a frequency domain and information on atransmission bandwidth of the localized SRS, and the localized SRS maybe transmitted in a frequency band indicated by the information on thestarting position in the specific symbol and the information on thetransmission bandwidth of the localized SRS.

The control information may further include information on atransmission starting position of the uplink control channel in afrequency domain, and the localized SRS and the uplink control channelmay be multiplexed and transmitted in the specific symbol based on theinformation on the transmission starting position of the uplink controlchannel in the frequency domain.

A symbol-wise orthogonal cover code (OCC) may be applied to the uplinkcontrol channel transmitted in the specific symbol and the uplinkcontrol transmitted in the adjacent symbol.

The method may further include: receiving, from the BS, information on alocalized SRS transmission pattern for preventing overlap betweenlocalized SRS transmission bands per subframe every a predeterminednumber of subframes; and when the localized SRS and an uplink controlchannel in the specific symbol are multiplexed and transmitted in thespecific symbol of a first subframe, transmitting a localized SRS and anuplink control channel in a symbol of a second subframe having a sameindex as the specific symbol based on the information on the localizedSRS transmission pattern.

In another aspect of the present disclosure, provide herein is a UserEquipment (UE) for transmitting a sounding reference symbol (SRS) in awireless communication system. The UE may include: a receiver; atransmitter; and a processor. The processor may be configured to controlthe receiver to receive, from a base station (BS), control informationincluding a first instruction for instructing to transmit a localizedSRS and control the transmitter to transmit the localized SRS in aspecific symbol based on the first instruction.

The control information may further include a second instruction forinstructing to multiplex and transmit the SRS and an uplink controlchannel in the specific symbol, and the processor may be configured tocontrol the transmitter to transmit the multiplexed localized SRS anduplink control channel in the specific symbol based on the secondinstruction.

The processor may be configured to control the transmitter an uplinkcontrol channel or a whole-band SRS in a symbol adjacent to the specificsymbol.

The control information may further include information on a startingposition of the localized SRS in a frequency domain and information on atransmission bandwidth of the localized SRS, and the processor may beconfigured to control the transmitter to transmit the localized SRS in afrequency band indicated by the information on the starting position inthe specific symbol and the information on the transmission bandwidth ofthe localized SRS.

The control information may further include information on atransmission starting position of the uplink control channel in afrequency domain, and the processor may be configured to control thetransmitter to transmit the multiplexed localized SRS and uplink controlchannel in the specific symbol based on the information on thetransmission starting position of the uplink control channel in thefrequency domain.

The processor may be configured to control the transmitter to transmitthe uplink channel transmitted in the specific symbol and the uplinkcontrol transmitted in the adjacent symbol by applying a symbol-wiseorthogonal cover code thereto.

The processor may be configured to: control the receiver to receive,from the BS, information on a localized SRS transmission pattern forpreventing overlap between localized SRS transmission bands per subframeevery a predetermined number of subframes; and when the localized SRSand an uplink control channel in the specific symbol are multiplexed andtransmitted in the specific symbol of a first subframe, control thetransmitter to transmit the localized SRS and the uplink control channelin a symbol of a second subframe having a same index as the specificsymbol based on the information on the localized SRS transmissionpattern.

Advantageous Effects

According to embodiments of the present disclosure, localized SRStransmission can not only solve a UE's peak-to-average power ratio(PAPR) problem can be solved but also increase the degree of freedom formultiplexing of two or more different uplink channels. Therefore, thelocalized SRS transmission can be widely used in new RAT.

The effects that can be achieved through the embodiments of the presentdisclosure are not limited to what has been particularly describedhereinabove and other effects which are not described herein can bederived by those skilled in the art from the following detaileddescription.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention.

FIG. 1 is a block diagram for configurations of a base station 105 and auser equipment 110 in a wireless communication system 100.

FIG. 2a shows the series of blockage event duration in Table 10 duringwhich important blockages occur, and FIG. 2b shows the blockage duration(t_(D)) in Table 2.

FIG. 3 is a diagram illustrating a wide beam composed of four narrowbeams.

FIG. 4 is a diagram illustrating the structure of a synchronizationsubframe.

FIG. 5 is a diagram illustrating a beam scanning period and a resourcearea (for example, 5×N ms period).

FIG. 6 is a diagram transmission of SRSs corresponding to UE beam IDs(the number of UE Tx beam IDs=8).

FIG. 7 is a diagram illustrating the structure of a subframe where TDMis applied to data and control channels.

FIG. 8 is a diagram illustrating interference caused by different ULresource configurations between cells.

FIG. 9 is a diagram illustrating multiplexing of an xPUCCH and alocalized SRS in the case of localized SRS transmission.

FIG. 10 is a diagram illustrating localized SRS transmission patterns.

FIG. 11 is a diagram illustrating the concatenation of a symbol forwhole-band SRS transmission, a symbol for localized SRS transmission,and a symbol for localized xPUCCH transmission.

FIG. 12 is a diagram illustrating the concatenation of a symbol forxPUCCH transmission, a symbol for localized SRS transmission, and asymbol for localized xPUCCH transmission.

FIG. 13 is a diagram illustrating a time OCC available area in an xPUCCHwhen an xPUCCH symbol, a localized SRS symbol, and a localized xPUCCHsymbol are concatenated.

BEST MODE

Reference will now be made in detail to the preferred embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings. In the following detailed description of thedisclosure includes details to help the full understanding of thepresent disclosure. Yet, it is apparent to those skilled in the art thatthe present disclosure can be implemented without these details. Forinstance, although the following descriptions are made in detail on theassumption that a mobile communication system includes 3GPP LTE system,the following descriptions are applicable to other random mobilecommunication systems in a manner of excluding unique features of the3GPP LTE.

Occasionally, to prevent the present disclosure from getting vaguer,structures and/or devices known to the public are skipped or can berepresented as block diagrams centering on the core functions of thestructures and/or devices. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Besides, in the following description, assume that a terminal is acommon name of such a mobile or fixed user stage device as a userequipment (UE), a mobile station (MS), an advanced mobile station (AMS)and the like. And, assume that a base station (BS) is a common name ofsuch a random node of a network stage communicating with a terminal as aNode B (NB), an eNode B (eNB), an access point (AP) and the like.Although the present specification is described based on IEEE 802.16msystem, contents of the present disclosure may be applicable to variouskinds of other communication systems.

In a mobile communication system, a user equipment is able to receiveinformation in downlink and is able to transmit information in uplink aswell. Information transmitted or received by the user equipment node mayinclude various kinds of data and control information. In accordancewith types and usages of the information transmitted or received by theuser equipment, various physical channels may exist.

The embodiments of the present disclosure can be applied to variouswireless access systems such as Code Division Multiple Access (CDMA),Frequency Division Multiple Access (FDMA), Time Division Multiple Access(TDMA), Orthogonal Frequency Division Multiple Access (OFDMA), SingleCarrier Frequency Division Multiple Access (SC-FDMA), etc. CDMA may beimplemented as a radio technology such as Universal Terrestrial RadioAccess (UTRA) or CDMA2000. TDMA may be implemented as a radio technologysuch as Global System for Mobile communications (GSM)/General packetRadio Service (GPRS)/Enhanced Data Rates for GSM Evolution (EDGE). OFDMAmay be implemented as a radio technology such as IEEE 802.11 (Wi-Fi),IEEE 802.16 (WiMAX), IEEE 802.20, Evolved UTRA (E-UTRA), etc. UTRA is apart of Universal Mobile Telecommunications System (UMTS). 3GPP LTE is apart of Evolved UMTS (E-UMTS) using E-UTRA, adopting OFDMA for DL andSC-FDMA for UL. LTE-Advanced (LTE-A) is an evolution of 3GPP LTE.

Moreover, in the following description, specific terminologies areprovided to help the understanding of the present disclosure. And, theuse of the specific terminology can be modified into another form withinthe scope of the technical idea of the present disclosure.

FIG. 1 is a block diagram for configurations of a base station 105 and auser equipment 110 in a wireless communication system 100.

Although one base station 105 and one user equipment 110 (D2D userequipment included) are shown in the drawing to schematically representa wireless communication system 100, the wireless communication system100 may include at least one base station and/or at least one userequipment.

Referring to FIG. 1, a base station 105 may include a transmitted (Tx)data processor 115, a symbol modulator 120, a transmitter 125, atransceiving antenna 130, a processor 180, a memory 185, a receiver 190,a symbol demodulator 195 and a received data processor 197. And, a userequipment 110 may include a transmitted (Tx) data processor 165, asymbol modulator 170, a transmitter 175, a transceiving antenna 135, aprocessor 155, a memory 160, a receiver 140, a symbol demodulator 155and a received data processor 150. Although the base station/userequipment 105/110 includes one antenna 130/135 in the drawing, each ofthe base station 105 and the user equipment 110 includes a plurality ofantennas. Therefore, each of the base station 105 and the user equipment110 of the present disclosure supports an MIMO (multiple input multipleoutput) system. And, the base station 105 according to the presentdisclosure may support both SU-MIMO (single user-MIMO) and MU-MIMO(multi user-MIMO) systems.

In downlink, the transmitted data processor 115 receives traffic data,codes the received traffic data by formatting the received traffic data,interleaves the coded traffic data, modulates (or symbol maps) theinterleaved data, and then provides modulated symbols (data symbols).The symbol modulator 120 provides a stream of symbols by receiving andprocessing the data symbols and pilot symbols.

The symbol modulator 120 multiplexes the data and pilot symbols togetherand then transmits the multiplexed symbols to the transmitter 125. Indoing so, each of the transmitted symbols may include the data symbol,the pilot symbol or a signal value of zero. In each symbol duration,pilot symbols may be contiguously transmitted. In doing so, the pilotsymbols may include symbols of frequency division multiplexing (FDM),orthogonal frequency division multiplexing (OFDM), or code divisionmultiplexing (CDM).

The transmitter 125 receives the stream of the symbols, converts thereceived stream to at least one or more analog signals, additionallyadjusts the analog signals (e.g., amplification, filtering, frequencyupconverting), and then generates a downlink signal suitable for atransmission on a radio channel. Subsequently, the downlink signal istransmitted to the user equipment via the antenna 130.

In the configuration of the user equipment 110, the receiving antenna135 receives the downlink signal from the base station and then providesthe received signal to the receiver 140. The receiver 140 adjusts thereceived signal (e.g., filtering, amplification and frequencydownconverting), digitizes the adjusted signal, and then obtainssamples. The symbol demodulator 145 demodulates the received pilotsymbols and then provides them to the processor 155 for channelestimation.

The symbol demodulator 145 receives a frequency response estimated valuefor downlink from the processor 155, performs data demodulation on thereceived data symbols, obtains data symbol estimated values (i.e.,estimated values of the transmitted data symbols), and then provides thedata symbols estimated values to the received (Rx) data processor 150.The received data processor 150 reconstructs the transmitted trafficdata by performing demodulation (i.e., symbol demapping, deinterleavingand decoding) on the data symbol estimated values.

The processing by the symbol demodulator 145 and the processing by thereceived data processor 150 are complementary to the processing by thesymbol modulator 120 and the processing by the transmitted dataprocessor 115 in the base station 105, respectively.

In the user equipment 110 in uplink, the transmitted data processor 165processes the traffic data and then provides data symbols. The symbolmodulator 170 receives the data symbols, multiplexes the received datasymbols, performs modulation on the multiplexed symbols, and thenprovides a stream of the symbols to the transmitter 175. The transmitter175 receives the stream of the symbols, processes the received stream,and generates an uplink signal. This uplink signal is then transmittedto the base station 105 via the antenna 135.

In the base station 105, the uplink signal is received from the userequipment 110 via the antenna 130. The receiver 190 processes thereceived uplink signal and then obtains samples. Subsequently, thesymbol demodulator 195 processes the samples and then provides pilotsymbols received in uplink and a data symbol estimated value. Thereceived data processor 197 processes the data symbol estimated valueand then reconstructs the traffic data transmitted from the userequipment 110.

The processor 155/180 of the user equipment/base station 110/105 directsoperations (e.g., control, adjustment, management, etc.) of the userequipment/base station 110/105. The processor 155/180 may be connectedto the memory unit 160/185 configured to store program codes and data.The memory 160/185 is connected to the processor 155/180 to storeoperating systems, applications and general files.

The processor 155/180 may be called one of a controller, amicrocontroller, a microprocessor, a microcomputer and the like. And,the processor 155/180 may be implemented using hardware, firmware,software and/or any combinations thereof. In the implementation byhardware, the processor 155/180 may be provided with such a deviceconfigured to implement the present disclosure as ASICs (applicationspecific integrated circuits), DSPs (digital signal processors), DSPDs(digital signal processing devices), PLDs (programmable logic devices),FPGAs (field programmable gate arrays), and the like.

Meanwhile, in case of implementing the embodiments of the presentdisclosure using firmware or software, the firmware or software may beconfigured to include modules, procedures, and/or functions forperforming the above-explained functions or operations of the presentdisclosure. And, the firmware or software configured to implement thepresent disclosure is loaded in the processor 155/180 or saved in thememory 160/185 to be driven by the processor 155/180.

Layers of a radio protocol between a user equipment/base station and awireless communication system (network) may be classified into 1st layerL1, 2nd layer L2 and 3rd layer L3 based on 3 lower layers of OSI (opensystem interconnection) model well known to communication systems. Aphysical layer belongs to the 1st layer and provides an informationtransfer service via a physical channel. RRC (radio resource control)layer belongs to the 3rd layer and provides control radio resourcedbetween UE and network. A user equipment and a base station may be ableto exchange RRC messages with each other through a wirelesscommunication network and RRC layers.

In the present specification, although the processor 155/180 of the userequipment/base station performs an operation of processing signals anddata except a function for the user equipment/base station 110/105 toreceive or transmit a signal, for clarity, the processors 155 and 180will not be mentioned in the following description specifically. In thefollowing description, the processor 155/180 can be regarded asperforming a series of operations such as a data processing and the likeexcept a function of receiving or transmitting a signal without beingspecially mentioned.

For UE Tx beam tracking, a UE needs to transmit an SRS for eachcandidate Tx beam of the UE. However, if SRSs are transmitted towardmany beam directions (in accordance with a UE's Tx beam set for alldirections), it may result in significant resource waste. Accordingly,the present disclosure proposes a method of performing an adaptive UE Txbeam tracking by performing SRS transmission flexibly according to UEpattern changes.

First, Table 1 below shows details of SRS transmission in the 3GPPLTE/LTE-A system.

TABLE 1 A UE shall transmit Sounding Reference Symbol (SRS) on perserving cell SRS resources based on two trigger types: trigger type 0:higher layer signalling trigger type 1: DCI formats 0/4/1A for FDD andTDD and DCI formats 2B/2C/2D for TDD. In case both trigger type 0 andtrigger type 1 SRS transmissions would occur in the same subframe in thesame serving cell, the UE shall only transmit the trigger type 1 SRStransmission. A UE may be configured with SRS parameters for triggertype 0 and trigger type 1 on each serving cell. The following SRSparameters are serving cell specific and semi-statically configurable byhigher layers for trigger type 0 and for trigger type 1. Transmissioncomb  

 , as defined in subclause 5.5.3.2 of [3] for trigger type 0 and eachconfiguration of trigger type 1 Starting physical resource blockassignment n_(RRC) , as defined in subclause 5.5.3.2 of [3] for triggertype 0 and each configuration of trigger type 1 duration: single orindefinite (until disabled), as defined in [11] for trigger type 0srs-ConfigIndex I_(SRS) for SRS periodicity T_(SRS) and SRS subframeoffset T_(offset) , as defined in Table 8.2-1 and Table 8.2-2 fortrigger type 0 and SRS periodicity T_(SRS,1), and SRS subframe offsetT_(SRS,1) , as defined in Table 8.2-4 and Table 8.2-5 trigger type 1 SRSbandwidth B_(SRS) , as defined in subclause 5.5.3.2 of [3] for triggertype 0 and each configuration of trigger type 1 Frequency hoppingbandwidth, b_(hop) , as defined in subclause 5.5.3.2 of [3] for triggertype 0 Cyclic shift n_(SRS) ^(CS) , as defined in subclause 5.5.3.1 of[3] for trigger type 0 and each configuration of trigger type 1 Numberof antenna ports N_(p) for trigger type 0 and each configuration oftrigger type 1 For trigger type 1 and DCI format 4 three sets of SRSparameters, srs- ConfigApDCI-Format4, are configured by higher layersignalling. The 2-bit SRS request field [4] in DCI format 4 indicatesthe SRS parameter set given in Table 8.1-1. For trigger type 1 and DCIformat 0, a single set of SRS parameters, srs-ConfigApDCI-Format0, isconfigured by higher layer signalling. For trigger type 1 and DCIformats 1A/2B/2C/2D, a single common set of SRS parameters,srs-ConfigApDCI-Format1a2b2c, is configured by higher layer signalling.The SRS request field is 1 bit [4] for DCI formats 0/1A/2B/2C/2D, with atype 1 SRS triggered if the value of the SRS request field is set to′1′. A 1-bit SRS request field shall be included in DCI formats 0/1A forframe structure type 1 and 0/1A/2B/2C/2D for frame structure type 2 ifthe UE is configured with SRS parameters for DCI formats 0/1A/2B/2C/2Dby higher-layer signalling.

Table 2 below shows SRS request values for trigger type 1 of DCI format4 in the 3GPP LTE/LTE-A system.

TABLE 2 Value of SRS request field Description ′00′ No type 1 SRStrigger ′01′ The 1^(st) SRS parameter set configured by higher layers′10′ The 2^(nd) SRS parameter set configured by higher layers ′11′ The3^(rd) SRS parameter set configured by higher layers

Table 3 below shows additional details of the SRS transmission in the3GPP LTE/LTE-A system.

TABLE 3 The serving cell specific SRS transmission bandwidths C_(SRS)are configured by higher layers. The allowable values are given insubclause 5.5.3.2 of [3]. The serving cell specific SRS transmissionsub-frames are configured by higher layers. The allowable values aregiven in subclause 5.5.3.3 of [3]. For a TDD serving cell, SRStransmissions can occur in UpPTS and uplink subframes of the UL/DLconfiguration indicated by the higher layer parameter subframeAssignment for the serving cell. When closed-loop UE transmit antennaselection is enabled for a given serving cell for a UE that supportstransmit antenna selection, the index a(n_(SRS)), of the UE antenna thattransmits the SRS at time n_(SRS) is given by a(n_(SRS)) = n_(SRS) mod2, for both partial and full sounding bandwidth, and when frequencyhopping is disabled (i.e., b_(hop) ≥ B_(SRS)),${a\left( n_{SRS} \right)} = \left\{ {\begin{matrix}{\left( {n_{SRS} + \left\lfloor {n_{SRS}/2} \right\rfloor + {\beta \cdot \left\lfloor {n_{SRS}/K} \right\rfloor}} \right){mod}\; 2} & {{when}\mspace{14mu} K\mspace{14mu} {is}\mspace{14mu} {even}} \\{n_{SRS}{mod}\; 2} & {{when}\mspace{14mu} K\mspace{14mu} {is}\mspace{14mu} {odd}}\end{matrix},} \right.$ $\beta = \left\{ \begin{matrix}1 & {{{where}\mspace{14mu} k\mspace{14mu} {mod}\mspace{14mu} 4} = 0} \\0 & {otherwise}\end{matrix} \right.$ when frequency hopping is enabled (i.e. b_(hop) <B_(SRS)), where values B_(SRS), b_(hop), N_(b), and n_(SRS) are given insubclause 5.5.3.2 of [3], and$K = {\prod\limits_{b^{\prime} = b_{hop}}^{B_{SRS}}\; {N_{t}\mspace{14mu} \left( {{{where}\mspace{14mu} N_{b_{hop}}} = 1} \right.}}$regardless of the N_(b) value), except when a single SRS transmission isconfigured for the UE. If a UE is configured with more than one servingcell, the UE is not expected to transmit SRS on different antenna portssimultaneously. A UE may be configured to transmit SRS on N_(p) antennaports of a serving cell where N_(p) may be configured by higher layersignalling. For PUSCH transmission mode 1 N_(p)∈ {0,1,2,4} and for PUSCHtransmission mode 2 N_(p)∈ {0,1,2} with two antenna ports configured forPUSCH and N_(p)∈ {0,1,4} with 4 antenna ports configured for PUSCH. A UEconfigured for SRS transmission on multiple antenna ports of a servingcell shall transmit SRS for all the configured transmit antenna portswithin one SC-FDMA symbol of the same subframe of the serving cell. TheSRS transmission bandwidth and starting physical resource blockassignment are the same for all the configured antenna ports of a givenserving cell. A UE not configured with multiple TAGs shall not transmitSRS in a symbol whenever SRS and PUSCH transmissions happen to overlapin the same symbol. For TDD serving cell, when one SC-FDMA symbol existsin UpPTS of the given serving cell, it can be used for SRS transmission.When two SC-FDMA symbols exist in UpPTS of the given serving cell, bothcan be used for SRS transmission and for trigger type 0 SRS both can beassigned to the same UE. If a UE is not configured with multiple TAGs,or if a UE is configured with multiple TAGs and SRS and PUCCH format2/2a/2b happen to coincide in the same subframe in the same servingcell, The UE shall not transmit type 0 triggered SRS whenever type 0triggered SRS and PUCCH format 2/2a/2b transmissions happen to coincidein the same subframe; The UE shall not transmit type 1 triggered SRSwhenever type 1 triggered SRS and PUCCH format 2a/2b or format 2 withHARQ-ACK transmissions happen to coincide in the same subframe; The UEshall not transmit PUCCH format 2 without HARQ-ACK whenever type 1triggered SRS and PUCCH format 2 without HARQ-ACK transmissions happento coincide in the same subframe. If a UE is not configured withmultiple TAGs, or if a UE is configured with multiple TAGs and SRS andPUCCH happen to coincide in the same subframe in the same serving cell,The UE shall not transmit SRS whenever SRS transmission and PUCCHtransmission carrying HARQ-ACK and/or positive SR happen to coincide inthe same subframe if the parameter ackNackSRS-SimultaneousTransmissionis FALSE; For FDD-TDD and primary cell frame structure 1, the UE shallnot transmit SRS in a symbol whenever SRS transmission and PUCCHtransmission carrying HARQ-ACK and/or positive SR using shortened formatas defined in subclauses 5.4.1 and 5.4.2A of [3] happen to overlap inthe same symbol if the parameter ackNackSRS-SimultaneousTransmission isTRUE. Unless otherwise prohibited, the UE shall transmit SRS wheneverSRS transmission and PUCCH transmission carrying HARQ-ACK and/orpositive SR using shortened format as defined in subclauses 5.4.1 and5.4.2A of [3] happen to coincide in the same subframe if the parameterackNackSRS-SimultaneousTransmission is TRUE. A UE not configured withmultiple TAGs shall not transmit SRS whenever SRS transmission on anyserving cells and PUCCH transmission carrying HARQ-ACK and/or positiveSR using normal PUCCH format as defined in subclauses 5.4.1 and 5.4.2Aof [3] happen to coincide in the same subframe. In UpPTS, whenever SRStransmission instance overlaps with the PRACH region for preamble format4 or exceeds the range of uplink system bandwidth configured in theserving cell, the UE shall not transmit SRS. The parameterackNackSRS-SimultaneousTransmission provided by higher layers determinesif a UE is configured to support the transmission of HARQ-ACK on PUCCHand SRS in one subframe. If it is configured to support the transmissionof HARQ-ACK on PUCCH and SRS in one subframe, then in the cell specificSRS subframes of the primary cell UE shall transmit HARQ-ACK and SRusing the shortened PUCCH format as defined in subclauses 5.4.1 and5.4.2A of [3], where the HARQ-ACK or the SR symbol corresponding to theSRS location is punctured. This shortened PUCCH format shall be used ina cell specific SRS subframe of the primary cell even if the UE does nottransmit SRS in that subframe. The cell specific SRS subframes aredefined in subclause 5.5.3.3 of [3]. Otherwise, the UE shall use thenormal PUCCH format 1/1a/1b as defined in subclause 5.4.1 of [3] ornormal PUCCH format 3 as defined in subclause 5.4.2A of [3] for thetransmission of HARQ-ACK and SR. Trigger type 0 SRS configuration of aUE in a serving cell for SRS periodicity, T_(SRS), and SRS subframeoffset, T_(offset), is defined in Table 8.2-1 and Table 8.2-2, for FDDand TDD serving cell, respectively. The periodicity T_(SRS) of the SRStransmission is serving cell specific and is selected from the set {2,5, 10, 20, 40, 80, 160, 320} ms or subframes. For the SRS periodicityT_(SRS) of 2 ms in TDD serving cell, two SRS resources are configured ina half frame containing UL subframe(s) of the given serving cell. Type 0triggered SRS transmission instances in a given serving cell for TDDserving cell with T_(SRS) > 2 and for FDD serving cell are the subframessatisfying (10 · n_(f) + k_(SRS) − T_(offset))modT_(SRS) = 0, where forFDD k_(SRS) = {0, 1, . . . , 0} is the subframe index within the frame,for TDD serving cell k_(SRS) is defined in Table 8.2-3. The SRStransmission instances for TDD serving cell with T_(SRS) = 2 are thesubframes satisfying k_(SRS) − T_(offset). For TDD serving cell, and aUE configured for type 0 triggered SRS transmission in serving cell c,and the UE configured with the parameter EIMTA-MainConfigServCell-r12for serving cell c, if the UE does not detect an UL/DL configurationindication for radio frame m (as described in section 13.1), the UEshall not transmit trigger type 0 SRS in a subframe of radio frame mthat is indicated by the parameter eimta-HarqReferenceConfig-r12 as adownlink subframe unless the UE transmits PUSCH in the same subframe.Trigger type 1 SRS configuration of a UE in a serving cell for SRSperiodicity, T_(SRS,1), and SRS subframe offset, T_(offset,1), isdefined in Table 8.2-4 and Table 8.2-5, for FDD and TDD serving cell,respectively. The periodicity T_(SRS,1) of the SRS transmission isserving cell specific and is selected from the set {2, 5, 10} ms orsubframes. For the SRS periodicity T_(SRS,1) of 2 ms in TDD servingcell, two SRS resources are configured in a half frame containing ULsubframe(s) of the given serving cell. A UE configured for type 1triggered SRS transmission in serving cell c and not configured with acarrier indicator field shall transmit SRS on serving cell c upondetection of a positive SRS request in PDCCH/EPDCCH schedulingPUSCH/PDSCH on serving cell c. A UE configured for type 1 triggered SRStransmission in serving cell c and configured with a carrier indicatorfield shall transmit SRS on serving cell c upon detection of a positiveSRS request in PDCCH/EPDCCH scheduling PUSCH/PDSCH with the value ofcarrier indicator field corresponding to serving cell c. A UE configuredfor type 1 triggered SRS transmission on serving cell c upon detectionof a positive SRS request in subframe n of serving cell c shall commenceSRS transmission in the first subframe satisfying n + k, k ≥ 4 and (10 ·n_(f) + k_(SRS) − T_(offset,1))modT_(SRS,1) = 0 for TDD serving cell cwith T_(SRS,1) > 2 and for FDD serving cell c, (k_(SRS) −T_(offset,1))mod 5 = 0 for TDD serving cell c with T_(SRS,1) = 2 wherefor FDD serving cell c k_(SRS) = {0, 1, . . . , 9} is the subframe indexwithin the frame n_(f), for TDD serving cell c k_(SRS) is defined inTable 8.2-3. A UE configured for type 1 triggered SRS transmission isnot expected to receive type 1 SRS triggering events associated withdifferent values of trigger type 1 SRS transmission parameters, asconfigured by higher layer signalling, for the same subframe and thesame serving cell. For TDD serving cell c, and a UE configured withEIMTA-MainConfigServCell-r12 for a serving cell c, the UE shall nottransmit SRS in a subframe of a radio frame that is indicated by thecorresponding eIMTA-UL/DL-configuration as a downlink subframe. A UEshall not transmit SRS whenever SRS and a PUSCH transmissioncorresponding to a Random Access Response Grant or a retransmission ofthe same transport block as part of the contention based random accessprocedure coincide in the same subframe.

Table 4 below shows the subframe offset configuration (T_(offset)) andUE-specific SRS periodicity (T_(SRS)) for trigger type 0 in FDD.

TABLE 4 SRS Configuration SRS Periodicity Index I_(SRS) (ms) SRSsubframe Offset 0-1 2 I_(SRS) 2-6 5 I_(SRS) - 2    7-16 10 I_(SRS) - 7  17-36 20 I_(SRS) - 17  37-76 40 I_(SRS) - 37   77-156 80 I_(SRS) - 77 157-316 160 I_(SRS) - 157 317-636 320 I_(SRS) - 317  637-1023 reservedreserved

Table 5 below shows the subframe offset configuration (T_(offset)) andUE-specific SRS periodicity (T_(SRS)) for trigger type 0 in TDD.

TABLE 5 SRS Configuration SRS Periodicity Index I_(SRS) (ms) SRSsubframe Offset 0-1 2 I_(SRS) 2-6 5 I_(SRS) - 2    7-16 10 I_(SRS) - 7  17-36 20 I_(SRS) - 17  37-76 40 I_(SRS) - 37   77-156 80 I_(SRS) - 77 157-316 160 I_(SRS) - 157 317-636 320 I_(SRS) - 317  637-1023 reservedreserved

TABLE 6 SRS SRS SRS Configuration Periodicity subframe Index I_(SRS)(ms) Offset 0 2 0, 1 1 2 0, 2 2 2 1, 2 3 2 0, 3 4 2 1, 3 5 2 0, 4 6 2 1,4 7 2 2, 3 8 2 2, 4 9 2 3, 4 10-14 5 I_(SRS) - 10  15-24 10 I_(SRS) -15  25-44 20 I_(SRS) - 25  45-84 40 I_(SRS) - 45   85-164 80 I_(SRS) -85  165-324 160 I_(SRS) - 165 325-644 320 I_(SRS) - 325  645-1023reserved reserved

Table 7 shows k_(SRS) for TDD.

TABLE 7 subframe index n 1 6 1st 2nd 1st 2nd symbol symbol symbol symbolof of of of 0 UpPTS UpPTS 2 3 4 5 UpPTS UpPTS 7 8 9 k_(SRS) in case 0 12 3 4 5 6 7 8 9 UpPTS length of 2 symbols k_(SRS) in case 1 2 3 4 6 7 89 UpPTS length of 1 symbol

Table 8 below shows the subframe offset configuration (T_(offset,1)) andUE-specific SRS periodicity (T_(SRS,1)) for trigger type 1 in FDD.

TABLE 8 SRS SRS Configuration Periodicity SRS Subframe Index I_(SRS)(ms) Offset 0-1 2 I_(SRS) 2-6 5 I_(SRS) - 2  7-16 10 I_(SRS) - 7 17-31reserved reserved

Table 9 below shows the subframe offset configuration (T_(offset,1)) andUE-specific SRS periodicity (T_(SRS,1)) for trigger type 1 in TDD.

TABLE 9 SRS SRS Configuration Periodicity SRS Subframe Index I_(SRS)(ms) Offset 0 reserved reserved 1 2 0, 2 2 2 1, 2 3 2 0, 3 4 2 1, 3 5 20, 4 6 2 1, 4 7 2 2, 3 8 2 2, 4 9 2 3, 4 10-14 5 I_(SRS) - 10 15-24 10I_(SRS) - 15 25-31 reserved reserved

Table 10 below shows additional channel variation characteristics(blockage effects) of a channel above 6 GHz compared to a channel below6 GHz.

TABLE 10 Tx Rx Test Ref. Test description height height frequencyBlockage rate relative parameter [2] One blocker moving 2.2/1.2 m 1.2 m60 GHz Series of Blockage event (1 m/s) duration (threshold 5 dB) Horn(22.4 dBi, 12°) 780~1839 ms (Horn) Patch (4.3 dBi/2.2 dBi, 58°) 640~1539ms (Patch) 4 blockers moving Series of Blockage event duration(threshold 5 dB) 688 ms (Horn, average) 278 ms (Patch, average) [5] 1~15blockers moving 1.58/2.77 m 1.55 m 60 GHz Series of Blockage eventduration The horns (22.4 dBi, (Threshold 10 dB) (Threshold 20 dB) 12° inazimuth, about 300 ms (1~5 persons)  100 ms (1~5 persons)  10° inelevation) 350 ms (6~10 persons)  150 ms (6~10 persons)  The patches(about 3 dBi, 450 ms (11~15 persons) 300 ms (11~15 persons) 60° both inelevation and azimuth. The vertical polarization) [6] — — — 60 GHz 93 ms(Mean Drop Rate) [7] One blocker moving 1.1 m 0.75 m 67 GHz t_(D) = 230ms (average, Threshold 20 dB) (Walking speed) 20 dBi, 10° [8] Oneblocker moving 1.1 m 0.75 m 67 GHz t_(D) = 370 ms~820 ms (Walking speed)t_(decay) = 230 ms (mean), 20 dBi, 10° 92 ms (s.d) (Threshold 20 dB)t_(rising) = 220 ms (mean), 100 ms (s.d) (Threshold 20 dB)

FIG. 2 is a diagram illustrating blockage duration with reference toTable 10. Specifically, FIG. 2a shows the series of blockage eventduration in Table 10 during which important blockages occur, and FIG. 2bshows the blockage duration (t_(D)) in Table 2. That is, the series ofblockage event duration indicates the time during which importantblockages occur, and t_(D) indicates the period between occurrence of ablockage and the when blockage ends and the system goes back to a normalstate.

Table 11 shows a pattern relationship between a UE and t_(decay) andt_(rising).

TABLE 11 Walking Sprinting Swift Hand swing (0.6 m/s)[7] (10 m/s)[9] (43m/s) t_(decay), t_(rising) (ms) 150 ms 9 ms 2.093 ms (measure)(calculation) (calculation)

Although Table 11 shows that a blockage change is basically estimated toabout average 100 ms (the speed of a walking obstacle (4 km/h)), it canvary from 2 ms to hundreds of ms depending on UE's patterns andsurrounding environments.

Necessity for Beam Tracking

When multiple beams are properly placed, a wide beam can be defined asshown in FIG. 3.

FIG. 3 is a diagram illustrating a wide beam composed of four narrowbeams.

Referring to FIG. 3, the wide beam is defined using four sub-arrays. Thepresent disclosure assumes that a transmitter transmits asynchronization signal using the wide beam. In other words, it isassumed that the same Primary Synchronization Signal/SecondarySynchronization Signal/Physical Broadcast Channel (PSS/SSS/PBCH) istransmitted on all sub-arrays.

Meanwhile, when multiple beams are defined to cover a wide area, beamgain may decrease. To solve the above trade-off, additional power gaincan be provided by repeating transmission in the time domain. Based onthe repeated transmission, a structure of a synchronization subframe maybe shown in FIG. 4.

FIG. 4 is a diagram illustrating the structure of a synchronizationsubframe.

Specifically, FIG. 4 shows not only the structure of the synchronizationsubframe but also PSS/SSS/PBCH defined therein. In FIG. 4, blocks withthe same type of hatching indicate a group of Orthogonal FrequencyDivision Multiplexing (OFDM) symbols where the same RF beam group(defined using four sub-array beams) is applied. That is, four OFDMsymbols use the same multi-RF beam. In new RAT, based on the structureof FIG. 4, a beam scanning period can be generally configured as shownin FIG. 5.

FIG. 5 is a diagram illustrating a beam scanning period and a resourcearea (for example, 5×N ms period).

Since a beam scanning process basically has significant processingoverhead, beam scanning cannot be completed within a very short period.In addition, the temporal variation of a channel above 6 GHz is expectedto be much faster than that of a channel below 6 GHz due to theaforementioned additional channel elements. Moreover, in a cellularsystem, a Base Station (BS) may have a fixed beam configuration, whereasa UE may have different beams depending on serving cell locations,changes in its surrounding environment, UE behavior patterns, etc. Thatis, a Tx/Rx beam mismatch is highly likely to occur within a beamscanning period. To overcome the Tx/Rx beam mismatch, a beam trackingmethod is required.

In the case of downlink transmission, beam tracking can be performed byapplying a UE Rx beam to each of the BRSs shown in FIG. 4 and measuringReference Signal Received Power (RSRP) thereof. If reciprocity isestablished between Tx/Rx beam pairs (i.e., BS Tx beam/UE Rx beam pairand UE Tx beam/BS Rx beam pair) for downlink transmission, a Tx/Rx beampair obtained from each BRS can be applied to uplink transmission.Otherwise, an SRS may be used for uplink transmission. To achieve themost powerful uplink beam tracking, SRSs should be transmitted for allTx beam IDs of each UE. However, this SRS transmission may decrease aPhysical Uplink Shared Channel (PUSCH) transmission region, and thusuplink throughput may decrease.

FIG. 6 is a diagram transmission of SRSs corresponding to UE beam IDs(the number of UE Tx beam IDs=8).

It can be seen from FIG. 6 that as the number of UE beam IDs increases,the SRS transmission region increases. If periodic SRS transmission isintroduced to beam tracking for matching a pair of UE Tx beams and BS RXbeams, that is, for establishing UE Tx/BS Rx beam pairs, the number ofSRSs for fixed UE Tx candidate beams may be configured by higher layers(for example, a BS may inform the number of SRS transmissions for thefixed UE Tx candidate beams via higher layer signaling (e.g., RRCsignaling)). However, if aperiodic SRS transmission is introduced, anadditional SRS transmission region is required for additional UE Txcandidate beams. In addition, as the aperiodic SRS transmission istriggered by a UE or a BS, an SRS transmission configuration, which isgenerated for aperiodic beam tracking, may be presented differently ineach beam tracking subframe. Moreover, signaling information for thebeam tracking should be provided to UEs whenever the aperiodic SRStransmission is triggered. As a result, signaling overhead may increase.Therefore, a method of efficiently arranging an SRS transmission regionand a PUSCH transmission region and a method of reducing signalingoverhead thereof are required.

FIG. 7 is a diagram illustrating the structure of a subframe where TDMis applied to data and control channels.

Specifically, FIG. 7 shows that TDM is applied to data and controlchannels in one subframe. In FIG. 7, the hatched area represents aDownlink (DL) control region (i.e., a resource region in which a DLcontrol channel is transmitted), and the black area represents an Uplink(UL) control region (i.e., a resource region in which a UL controlchannel is transmitted). The unmarked area in the subframe of FIG. 7 canbe used for DL or UL data transmission. According to this structure, itis possible to transmit DL data and receive UL ACK/NACK in a singlesubframe since DL transmission and UL transmission are sequentiallyperformed in the single subframe. Consequently, when a data transmissionerror occurs, it is possible to reduce a time required until data isretransmitted, thereby minimizing the latency of the overall datatransmission.

In the above subframe structure where the data and control channels areTime Division Multiplexed (TDMed), a time gap is required to allow a BSand a UE to switch from transmission mode to reception mode or viceversa. To this end, some Orthogonal Frequency Division Multiplexing(OFDM) symbols at the DL-to-UL switching time can be configured as aGuard Period (GP) in this subframe structure.

In FIG. 7, the hatched area represents a transmission region for aPhysical Downlink Control Channel (PDCCH) carrying Downlink ControlInformation (DCI), and the last symbol is a transmission region for aPhysical Uplink Control Channel (PUCCH) carrying Uplink ControlInformation (UCI). Here, the DCI corresponding to control informationtransmitted from an eNB (BS) to a UE may include information on a cellconfiguration that the UE should know, DL-specific information such asDL scheduling, UL-specific information such as a UL grant, etc. The UCIcorresponding to control information transmitted from a UE to a BS mayinclude an HARQ ACK/NACK report on DL data, a CSI report on a DL channelstate, a Scheduling Request (SR), etc.

In FIG. 7, the unmarked area can be used for a data channel fortransmitting DL data (e.g., Physical Downlink Shared Channel (PDSCH)) ora data channel for transmitting UL data (e.g., Physical Uplink SharedChannel (PUSCH)). According to this structure, an eNB (BS) can transmitDL data and receive an HARQ ACK/NACK signal from a UE in response to theDL data in a single subframe since DL transmission and UL transmissionare sequentially performed in the single subframe. Consequently, when adata transmission error occurs, it is possible to reduce a time takenuntil data retransmission, thereby minimizing the latency of the overalldata transmission.

In such a self-contained subframe structure, a time gap is required toallow a BS and a UE to switch from transmission mode to reception modeor vice versa. To this end, some OFDM symbols at the DL-to-UL switchingtime can be configured as a GP in this self-contained subframestructure.

In the new RAT system, the following four subframe types may beconsidered as examples of configurable self-contained subframe types. Inthe four subframe types, individual regions are arranged within asubframe in time order.

1) DL control region+DL data region+GP+UL control region

2) DL control region+DL data region

3) DL control region+GP+UL data region+UL control region

4) DL control region+GP+UL data region

In new RAT, UL design for mitigating a peak-to-average power ratio(PAPR) problem can be considered owing to small cell coverage, UL OFDM,etc. In addition, if each UE performs SRS transmission over the wholeband (in the new RAT, an SRS may be represented as an xSRS), a new RATBS may fail in SRS detection due to limited transmission power.Considering the configurations of localized SRS transmission andfull-band SRS transmission from the perspective of UE transmissionpower, it is expected that the localized SRS transmission is performedmore times. For the above-described two reasons, that is, due to themitigation of the PAPR problem and the localized SRS transmission, a UEis allowed to perform multiplexing of two or more different UL channelsmore freely.

When two or more UL channels are multiplexed, inter-cell interferencemay occur due to different UL channel configurations between neighboringcells. If the same channel is configured on the same resource (k, l) ineach cell, each cell may easily detects its UL channel by applyingdifferent cyclic shifts to UL channels. However, if the resources of aUL channel overlaps with those of another UL channel with a differentsequence or signal, its detection is not easy. Accordingly, the mostimportant issue in multiplexing different UL channels is that whendifferent cells have different UL channel transmission configurations,resource allocation locations should not overlap with each other toreduce inter-cell interference, or when different channel sequences orsignals are generated, if the sequences or signals have the same format,each BS becomes capable of detecting the channels although they overlapwith each other.

FIG. 8 is a diagram illustrating interference caused by different ULresource configurations between cells.

As shown in FIG. 8, inter-cell interference may occur between an SRS anda physical UL channel (xPUCCH) due to the SRS configuration of cell Aand the xPUCCH configuration of cell B. To cancel the inter-cellinterference, the following method may be applied.

1) An SRS and xPUCCH formats 1, 1a, and 1b are designed using a ZadoffChu (ZC) sequence.

r _(u,v) ^((α))(n)=e ^(jαn) r _(u,v)(n), 0≤n<M _(sc) ^(RS)

2) In each channel (i.e., an SRS, an xPUCCH, etc.), u for configuringthe root of the ZC sequence is determined using a different grouphopping method.

u=(f _(gh)(n _(s))+f _(ss))mod 30, where f _(ss) ^(xPUCCH) =n _(ID)^(RS) mod 30, f _(ss) ^(SRS) =n _(ID) ^(RS) mod 30

3) xPUCCH:

-   -   n_(ID) ^(RS)=N_(ID) ^(cell) if no value for n_(ID) ^(PUCCH) is        configured by higher layers,    -   n_(ID) ^(RS)=n_(ID) ^(xPUCCH) otherwise.

Sounding reference signals:

-   -   n_(ID) ^(RS)=N_(ID) ^(cell) if no value for n_(ID) ^(xSRS) is        configured by higher layers, n_(ID) ^(RS)=n_(ID) ^(xSRS)        otherwise.

According to this method, each BS may detect individual channels bydetecting different ZC sequences from an SRS and an xPUCCH even thoughinter-cell interference exists between the SRS and xPUCCH. However, themethod is available when different channels use sequences satisfying theorthogonality condition. In particular, if the resources of an SRSoverlap with those of another channel, for example, an xPUCCH format(e.g., xPUCCH format 2) in terms of signal generation, inter-cellinterference may occur, and as a result, performance may be degraded. Inthe following embodiments, various methods are proposed to solve such aproblem.

Embodiment 1

In Embodiment 1, provided is a method of configuring a parameter forusing a localized SRS and multiplexing the localized SRS with another ULchannel.

A BS may transmit to a UE a Cell-specific Localized SRS Enable flag overa cell-specific physical DL control channel (e.g., xPDCCH) or throughhigher layer signaling. In addition, the BS may transmit to the UE aflag indicating that multiplexing of an SRS and another UL channel isdetermined or performed over a UE-specific physical DL control channel(e.g., xPDCCH) or through higher layer signaling.

The BS may also transmit to the UE a UE-specific Localized SRS Enableflag over a UE-specific physical DL control channel (xPDCCH) or throughhigher layer signaling. Based on an indicator (i.e., Localized SRSEnable flag) indicating whether each UE needs to transmit a localizedSRS or a normal SRS (including whole band transmission), the UEtransmits either the localized SRS or the normal SRS (including thewhole band transmission). For example, when the Localized SRS Enableflag is enabled, the UE transmits the localized SRS.

Location of localized SRS starting resource element (RE) or resourceblock (RB) (K_(localized_SRS) ^((p))) (for example, the startinglocation of the localized SRS in the frequency domain): The BS maydetermine the location of the starting RE or RB of the localized SRS andthen inform the UE of the location on a specific antenna port (e.g.,antenna port index p) over a cell-specific xPDCCH or through higherlayer signaling.

Localized SRS bandwidth configuration: The BS may transmit to the UEinformation on the configuration of a localized SRS transmissionbandwidth over a UE-specific xPDCCH or through higher layer signaling.As a fraction of the entire UL system bandwidth, the localized SRStransmission bandwidth can be represented as follows:

${B_{localized\_ SRS} = \left\lfloor \frac{B_{sys}}{M} \right\rfloor},$

where M is an integer.

When multiplexing of the SRS and the other UL channel is determined, theBS may transmit the transmission location (K_(localized_xPUCCH) ^((p)))of the localized SRS, which is to be transmitted on a specific antennaport over a channel (e.g., xPUCCH), to the UE through an xPDCCH orthrough higher layer signaling.

Table 12 below shows the localized SRS bandwidth configuration.

TABLE 12 SRS SRS- SRS- SRS- SRS- bandwidth Bandwidth Bandwidth BandwidthBandwidth configuration B_(localized)_SRS = 0 B_(localized)_SRS = 1B_(localized)_SRS = 2 B_(localized)_SRS = 3 C_(localized)_SRS m_(SRS,0)m_(SRS,1) m_(SRS,2) m_(SRS,3) 0 24 12 6 3 1 16 8 4 2

FIG. 9 is a diagram illustrating multiplexing of an xPUCCH and alocalized SRS in the case of localized SRS transmission.

For example, assuming that the Cell-specific Localized SRS Enable flagis enabled, K_(localized_SRS) ^((p))=1 RB (i.e., RB index 1),C_(localized_SRS) (localized SRS bandwidth configuration)=0, andK_(localized_xPUCCH) ^((p))=25 RB (i.e., RB index 25), an SRS can bemultiplexed with an xPUCCH as shown in FIG. 9.

As shown in FIG. 9, when the localized SRS is enabled, a UE may beallocated an SRS resource and an xPUCCH resource at the same time,multiplex the SRS and the xPUCCH, and then transmit the multiplexed SRSand xPUCCH to a BS.

Embodiment 2: Subframe Structure where Localized SRS and Whole-Band SRSare Transmitted

In Embodiment 2, provided is a subframe structure for transmitting alocalized SRS and a whole-band SRS. In Embodiment 2-1, which is asub-embodiment of Embodiment 2, provided is a method by which a BSinforms each UE of the location of a localized SRS in a subframeincluding the localized SRS and a UL control channel in advance using aphysical DL channel or through higher layer signaling by consideringreciprocity with a DL channel.

According to Embodiment 2-2, which is another sub-embodiment ofEmbodiment 2, when localized SRS transmission is configured in subframe#n, the locations of localized SRSs in n-th to k-th subframes may beconfigured according to a pattern. In this case, a BS may inform a UE ofthe value of k over a physical layer channel or through higher layersignaling. Information on the localized SRS location pattern in the n-thto k-th subframes may be pre-shared by the BS and UE. Alternatively, theBS may transmit the information to the UE.

TABLE 13 k n n + 1 n + 2 n + 3 2 Odd Even — — 3 α α + 1 α + 2 — 4 α α +1 α + 2 α + 3

$\arg\limits_{\alpha}\frac{N_{RB}^{UL}}{N_{sb}^{SRS}}$

is 0. In this case, N_(sb) ^(SRS)=m·X may be configured on an RB basis,an RE basis, or a predetermined unit basis (where m is an integer).

FIG. 10 is a diagram illustrating localized SRS transmission patterns.

In particular, FIG. 10 (a) shows a localized SRS transmission pattern inthe case of k=2, and FIG. 10 (b) shows a localized SRS transmissionpattern in the case of k=3.

According to the patterns shown in FIG. 10, even if a UE intends totransmit a localized SRS in subframe #n, it is not necessary to allocatelocalized SRSs to subframe #n+k for the corresponding UE. As shown inFIG. 10 (a), the localized SRS transmission pattern may be configuredsuch that frequency resources for localized SRS transmission allocatedto a first subframe (subframe #n) do not overlap with those allocated toa second subframe (subframe #n+1). As shown in FIG. 10 (b), thelocalized SRS transmission pattern may be configured such that frequencyresources for localized SRS transmission allocated to a first subframe(subframe #n), a second subframe (subframe #n+1), and a third subframe(subframe #n) do not overlap with each other.

According to the above method, UE power is concentrated on a specificfrequency resource or a frequency resource region preferred by a UE inorder to allocate desired UL data resources, thereby improving the SRSdetection capability of a BS and achieving the efficient use of SRSresources and UL control channel resources.

Embodiment 3

In Embodiment 3, provided is a subframe structure where a whole-bandSRS, a localized SRS, and a UL control channel are transmitted alltogether.

FIG. 11 is a diagram illustrating the concatenation of a symbol forwhole-band SRS transmission, a symbol for localized SRS transmission,and a symbol for localized xPUCCH transmission.

Specifically, FIG. 11 shows Embodiment 3-1, a sub-embodiment ofEmbodiment 3. In Embodiment 3-1, it is proposed that when a localizedSRS, a whole-band SRS, and a UL control channel are configured by a BSto be transmitted together in subframe #n, if the whole-band SRS isconfigured to be transmitted in symbol #k, the localized SRS and ULcontrol channel are transmitted in symbol #k+l or #k−l. In this case, lis an integer (for example, 1=1 or 2), and in particular, l is set to asmall integer by considering channel aging. FIG. 11 shows that thelocalized SRS and UL control channel are transmitted together in symbol#k−l.

FIG. 12 is a diagram illustrating the concatenation of a symbol forxPUCCH transmission, a symbol for localized SRS transmission, and asymbol for localized xPUCCH transmission.

In Embodiment 3-2, which is another sub-embodiment of Embodiment 3, itis proposed that when a localized SRS, a whole-band SRS, and an xPUCCHare configured by a BS to be transmitted together in subframe #n, if thewhole-band xPUCCH is configured to be transmitted in symbol #k, thelocalized SRS and the localized xPUCCH are configured to be transmittedin symbol #k+l or #k−l.

Embodiment 4

In the subframe structure of Embodiment 3, a symbol-wise orthogonalcover code (OCC) may be applied to control channels on consecutive orneighboring symbols by considering the frequency-domain OCC (e.g., Walshcode, DFT vector, etc.). The operation of applying an OCC to controlchannels on consecutive or neighboring symbols may be performed by thefollowing UEs.

-   -   UEs that are located at the edge of a cell and require the        extension of cell coverage    -   UEs that require the improvement of channel reception        performance to receive a UL control channel (e.g., UEs having        severe frequency-selective fading on resources allocated for a        UL control channel, UEs suffering from a decrease in reception        power due to a sudden blockage, etc.)    -   UEs instructed by a BS to use allocated resources for a UL        control channel

FIG. 13 is a diagram illustrating a time OCC available area in an xPUCCHwhen an xPUCCH symbol, a localized SRS symbol, and a localized xPUCCHsymbol are concatenated.

As shown in FIG. 13, the location of an xPUCCH starting symbol,K_(localized_xPUCCH) ^((p),OCC) in symbol #k of subframe #n may beconfigured for a UE. It is assumed that the frequency-domain OCC of [1,1, 1, 1] is generated over 4 REs in symbol #k. If a localized SRS andxPUCCH are configured in symbol #k−l and the frequency-domain OCC forthe xPUCCH is set to [1, 1, −1, −1], the symbol-wise OCC, w(i) isdetermined according to how a BS and a UE use the xPUCCH. If twoconsecutive xPUCCH symbols are bundled, w(i) may be set to [1 1] toincrease reception power in first two REs, or it may be set to [−1 1] toincrease reception power in last two REs.

When the xPUCCH symbol is consecutive or adjacent to the localized SRSand xPUCCH symbols, if the symbol-wise OCC is applied to adjacentxPUCCHs symbols, the received power of the xPUCCH may increase so thatthe xPUCCH reception performance of the BS may be improved.

As described above, the localized SRS transmission may not only solvethe UE's PAPR problem but also increase the degree of freedom formultiplexing of two or more different UL channels. Therefore, thelocalized SRS transmission can be widely used in the new RAT.

The above-described embodiments correspond to combinations of elementsand features of the present disclosure in prescribed forms. And, therespective elements or features may be considered as selective unlessthey are explicitly mentioned. Each of the elements or features can beimplemented in a form failing to be combined with other elements orfeatures. Moreover, it is able to implement an embodiment of the presentdisclosure by combining elements and/or features together in part. Asequence of operations explained for each embodiment of the presentdisclosure can be modified. Some configurations or features of oneembodiment can be included in another embodiment or can be substitutedfor corresponding configurations or features of another embodiment. And,it is apparently understandable that an embodiment is configured bycombining claims failing to have relation of explicit citation in theappended claims together or can be included as new claims by amendmentafter filing an application.

Those skilled in the art will appreciate that the present disclosure maybe carried out in other specific ways than those set forth hereinwithout departing from the essential characteristics of the presentdisclosure. The above embodiments are therefore to be construed in allaspects as illustrative and not restrictive. The scope of the disclosureshould be determined by the appended claims and their legal equivalents,not by the above description, and all changes coming within the meaningand equivalency range of the appended claims are intended to be embracedtherein.

INDUSTRIAL APPLICABILITY

The method of transmitting an SRS in a wireless communication system andterminal for the same can be applied to various wireless communicationsystems including the 3GPP LTE/LTE-A system, the 5G communicationsystem, etc.

1. A method of transmitting a sounding reference symbol (SRS) by a userequipment (UE) in a wireless communication system, the methodcomprising: receiving, from a base station (BS), control informationincluding a first instruction for instructing to transmit a localizedSRS; and transmitting the localized SRS in a specific symbol based onthe first instruction.
 2. The method of claim 1, wherein the controlinformation further includes a second instruction for instructing tomultiplex and transmit the localized SRS and a first uplink controlchannel in the specific symbol, and wherein the localized SRS and thefirst uplink control channel are multiplexed and transmitted in thespecific symbol based on the second instruction.
 3. The method of claim2, further comprising transmitting a second uplink control channel or awhole-band SRS in a symbol adjacent to the specific symbol.
 4. Themethod of claim 2, wherein the control information further includesinformation on a starting position of the localized SRS in a frequencydomain and information on a transmission bandwidth of the localized SRS,and wherein the localized SRS is transmitted in a frequency bandindicated by the information on the starting position in the specificsymbol and the information on the transmission bandwidth of thelocalized SRS.
 5. The method of claim 2, wherein the control informationfurther includes information on a transmission starting position of thefirst uplink control channel in a frequency domain, and wherein thelocalized SRS and the first uplink control channel are multiplexed andtransmitted in the specific symbol based on the information on thetransmission starting position of the first uplink control channel inthe frequency domain.
 6. The method of claim 3, wherein a symbol-wiseorthogonal cover code (OCC) is applied to the first uplink controlchannel transmitted in the specific symbol and the second uplink controlchannel transmitted in the adjacent symbol.
 7. The method of claim 2,further comprising: receiving, from the BS, information on a localizedSRS transmission pattern for preventing overlap between localized SRStransmission bands per subframe every a predetermined number ofsubframes; and when the localized SRS and the first uplink controlchannel in the specific symbol are multiplexed and transmitted in thespecific symbol of a first subframe, transmitting a second localized SRSand a third uplink control channel in a symbol of a second subframehaving a same index as the specific symbol based on the information onthe localized SRS transmission pattern.
 8. A User Equipment (UE) fortransmitting a sounding reference symbol (SRS) in a wirelesscommunication system, the UE comprising: a transceiver coupled to atleast one processor; and the at least one processor configured to:receive, from a base station (BS), control information including a firstinstruction for instructing to transmit a localized SRS, transmit thelocalized SRS in a specific symbol based on the first instruction. 9.The UE of claim 8, wherein the control information further includes asecond instruction for instructing to multiplex and transmit thelocalized SRS and a first uplink control channel in the specific symbol,and wherein the at least one processor is further configured to transmitthe multiplexed localized SRS and first uplink control channel in thespecific symbol based on the second instruction.
 10. The UE of claim 9,wherein the at least one processor is further configured to transmit asecond uplink control channel or a whole-band SRS in a symbol adjacentto the specific symbol.
 11. The UE of claim 9, wherein the controlinformation further includes information on a starting position of thelocalized SRS in a frequency domain and information on a transmissionbandwidth of the localized SRS, and wherein the at least one processoris further configured to transmit the localized SRS in a frequency bandindicated by the information on the starting position in the specificsymbol and the information on the transmission bandwidth of thelocalized SRS.
 12. The UE of claim 9, wherein the control informationfurther includes information on a transmission starting position of thefirst uplink control channel in a frequency domain, and wherein the atleast one processor is further configured to transmit the multiplexedlocalized SRS and first uplink control channel in the specific symbolbased on the information on the transmission starting position of thefirst uplink control channel in the frequency domain.
 13. The UE ofclaim 9, wherein the at least one processor is further configured totransmit a second uplink control channel or a whole-band SRS in a symboladjacent to the specific symbol, wherein a symbol-wise orthogonal covercode is applied to the first uplink control channel transmitted in thespecific symbol and the second uplink control channel transmitted in theadjacent symbol.
 14. The UE of claim 9, wherein the at least oneprocessor is further configured to: receive, from the BS, information ona localized SRS transmission pattern for preventing overlap betweenlocalized SRS transmission bands per subframe every a predeterminednumber of subframes, and when the localized SRS and the first uplinkcontrol channel in the specific symbol are multiplexed and transmittedin the specific symbol of a first subframe, control the transmitter totransmit a second localized SRS and a third uplink control channel in asymbol of a second subframe having a same index as the specific symbolbased on the information on the localized SRS transmission pattern. 15.The method of claim 1, further comprising transmitting a second uplinkcontrol channel or a whole-band SRS in a symbol adjacent to the specificsymbol.
 16. The method of claim 1, wherein the control informationfurther includes information on a starting position of the localized SRSin a frequency domain and information on a transmission bandwidth of thelocalized SRS, and wherein the localized SRS is transmitted in afrequency band indicated by the information on the starting position inthe specific symbol and the information on the transmission bandwidth ofthe localized SRS.
 17. The method of claim 1, further comprising:receiving, from the BS, information on a localized SRS transmissionpattern for preventing overlap between localized SRS transmission bandsper subframe every a predetermined number of subframes; and when thelocalized SRS and a first uplink control channel in the specific symbolare multiplexed and transmitted in the specific symbol of a firstsubframe, transmitting a localized SRS and a third uplink controlchannel in a symbol of a second subframe having a same index as thespecific symbol based on the information on the localized SRStransmission pattern.
 18. The UE of claim 8, wherein the at least oneprocessor is further configured to transmit a second uplink controlchannel or a whole-band SRS in a symbol adjacent to the specific symbol.19. The UE of claim 8, wherein the control information further includesinformation on a starting position of the localized SRS in a frequencydomain and information on a transmission bandwidth of the localized SRS,and wherein the processor is configured to control the transmitter totransmit the localized SRS in a frequency band indicated by theinformation on the starting position in the specific symbol and theinformation on the transmission bandwidth of the localized SRS.
 20. TheUE of claim 8, wherein the at least one processor is further configuredto: receive, from the BS, information on a localized SRS transmissionpattern for preventing overlap between localized SRS transmission bandsper subframe every a predetermined number of subframes, when thelocalized SRS and a first uplink control channel in the specific symbolare multiplexed and transmitted in the specific symbol of a firstsubframe, control the transmitter to transmit a localized SRS and athird uplink control channel in a symbol of a second subframe having asame index as the specific symbol based on the information on thelocalized SRS transmission pattern.